If the pad is separating from the board (coming unglued), then industrial strength contact cement or hot melt glue will tack it back down. Be sure the pad and board are dry first.

If you use hot melt glue, you&#39;ll get better adhesion if you warm the board a little bit (not a lot) with a heater. Do NOT overheat the board, just get the glass warm to the touch. Probably a good idea to crack the vent while you do this, and then seal it again after the board cools.